The present invention relates to a beater holder mounting structure used in a base drum to hold a beater, and more particularly to such a beater holder mounting structure which positively secures the beater to the polygonal shaft of the pedal unit of the base drum.
A pedal unit for a base drum, as shown in FIG. 1, is comprised of a base frame, a polygonal shaft revolvably supported between two upright supports raised from the base frame, a beater holder fastened to the polygonal shaft to hold a beater, spring means coupled between one end of the polygonal shaft and the base frame, and a pedal having a rear end hinged to the base frame and a front end coupled to the beater holder by a chain transmission. Referring to FIG. 2 and FIG. 1, the beater holder has a circular axle hole which receives the stem of the beater, and a screw hole perpendicularly extended from the axle hole to the periphery into which a tightening up screw is threaded and stopped against the periphery of the stem of the beater to fix the beater to the beater holder. When installed, the stem of the beater provide two friction resisting surfaces, one at the end of the tightening up screw and the other at the periphery of the circular axle hole opposite to the tightening up screw. Because the two friction resisting surfaces are spaced at about 180.degree., they are not insufficient to positively secure the stem of the beater to the beater holder. When beating, the beater is vibrated, and may be forced by the vibration force out of position. If the beater is not positively secured in position, the face of the drum may be damaged by the beater.